Clinicogenetic Risk Prognostication for First-Line Treatment of Symptomatic Follicular Lymphoma

Background: Follicular lymphoma (FL) is an indolent malignancy of germinal center B cells with highly variable patient outcomes. Recently, a 23-gene predictor score was proposed for predicting progression-free survival. In the past, we had shown that the m7-FLIPI, a clinico-genetic risk model, allows to improve patient stratification compared to clinical risk models alone. The multitude of prognostic tools in FL raises the question whether they identify common biology. Methods: In this study, we applied a modified risk score (MRS) to an independent gene-expression dataset of FL patients treated with rituximab in combination with chemotherapy. Results: Using supervised and unsupervised approaches, we showed that the MRS identifies patient groups with diverging outcomes in our dataset. In addition, using gene set enrichment and network identification, we discovered associations between the MRS, the m7-FLIPI, EZH2 mutation status and FOXP1 expression. Conclusions: Our findings lend support to expression of dark-zone related genes as a key determinant of poor outcome following rituximab and chemotherapy. All RNA samples were derived from formalin-fixed paraffin-embedded tissue blocks and processed using the Illumina Whole-Genome DASL assay. The study includes 137 gene expression samples from the BC Cancer Agency cohort.